The local chapter of the American Institute of Aeronautics and Astronautics hosted a luncheon today with John Dankanich, the iSAT program manager as speaker. iSAT stands for Iodine Satellite, and it is a Cubesat program to test iodine instead of xenon in a Hall thruster engine. Right now, there aren’t a lot of options for small satellite propulsion. Solid motors are one use only, liquid engines take a lot of weight and space, and hypergols will try to kill you. By letting the iodine sublimate, i.e. go directly from solid to gas, all you need is a little heat to turn on your engine.
This isn’t the kind of engine that will lift a payload from Earth to orbit, but it will allow orbit change, even inclination change. Dankanich spoke about the military uses, being able to put communication relays or observation satellites into the right orbit quickly, perhaps even a constellation. You could have a constellation of small, cheap satellites around the moon or Mars or Venus. As for myself, I was interested in the end-of-life uses for small satellites, to deorbit a spacecraft before it becomes space debris.
Another point in favor of iodine was the much lower pressure than the current xenon Hall thruster engines. It opens up the possibility of rapid-prototyping your tank and even a conformal design to fit in the available space. Iodine presents some challenges in terms of what materials it’s compatible with, but we ought to be able to handle that.
It was an interesting talk, and it sounds like they have hit the ground running with a lot of hardware ready to go or easily modified for this mission. I wish them a lot of success in the future.
If you’d like to follow iSAT’s progress, they are on Facebook at www.facebook.com/NASAisat .